A pre-tested HWInfo version of today’s release now also reliably shows GDDR6X temperatures. As the programmer told me, there is a lot of searching, trial and error and therefore a lot of work involved. However, HWInfo is the first publicly accessible tool to offer end users (and reviewers) the possibility of reading out these temperatures and also logging them. This step was actually long overdue, but even NVIDIA does not disclose all the information that you would actually need as a software publisher.
From my own tests I can confirm that the values listed here are plausible and I have also checked them. This includes the indirect measurement method with IR camera and the known delta of a referenced graphics board. The manufacturer also comments on the temperatures in his own blog, for example.
The software can be downloaded today from the official homepage. Download page